The invention relates to a high-vacuum coating apparatus having a tank of an electrically conductive material in which metal is converted to its vaporous phase by means of electrical energy for the performance of a coating process. For the production of a high current, at least one transformer having an iron core, a primary winding and a secondary winding is provided. One pole of the secondary winding is connected by an electrical conductor to a power feeder leading into the tank and the other pole is connected to the tank.
To convert a metal to the vapor phase by electrical energy a high current is necessary. Therefore, coating apparatus of the above kind are usually equipped with several high-current transformers. These transformers have heretofore been located in a pit underneath the high-vacuum coating apparatus. The two poles of the transformers were connected by copper bus bars and high-current cables to the evaporator of the high-vacuum coating apparatus. Especially the connection to the wall of the tank was configured as a bus bar of relatively large area so that heat could be dissipated by convection.
Arranging the transformers in a pit at a considerable distance from the tank involves relatively high costs, especially due to the relatively long high-current conductor that becomes necessary. Furthermore, it leads to the disadvantage that, after being assembled by the manufacturer for test-run purposes, the transformers with their high-current conductors have to be disassembled and later on reassembled at the customer's.